dispatch issue : how to get value from version-free variable?

I am creating a dispatch to get variable value from data card.

In the dispatch, a variable is set to "variable value from selected file data card", and the variable in data card is a version-free variable, the dispatch will use it to populate another variable in data card.

A simple dispatch is created for testing(see images below), when I run it, the OK message shows that the value is empty, which means dispatch was not able to get value from data card.

After a few tests, I found that it only works with non-version-free variable that has custom property attribute.

Does anyone use dispatch to get value from data card? any ideas would be greatly appreciated, thank you.

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